Preheat oven to 350F. Melt butter in a 3 quart saucepan. Remove shrimp from shells and add the shells to the butter. Saute for about 10 minutes, then add cognac and continue cooking for another two minutes. Remove shells from butter. Add shrimp to butter and saute until they are cooked. Remove shrimp from butter. Add flour to butter and stir well to combine leaving no dry spots. Add milk, crab stock, cream, paprika, salt, white pepper, and veggie seasoning. Stir with whisk and cook until thickened. Remove from heat, then add cooked shrimp, Gruyere cheese, crab meat, and lobster. Gently stir to combine, then set aside.